This invention relates, generally, to the use and structure of removable electronic circuit cards and, more specifically, to the connections between card modules on either a single card or on individual cards.
Various commercially available non-volatile memory cards that are becoming popular are extremely small and have different mechanical and/or electrical interfaces. Examples include the related MultiMediaCard (“MMC”) and Secure Digital (“SD”) memory cards that are available from SanDisk Corporation of Sunnyvale, Calif., assignee of the present application. There are other cards that conform to standards of the International Organization for Standardization (“ISO”) and the International Electrotechnical Commission (“IEC”), an example that is widely implemented being known as the ISO/IEC 7816 standard.
The physical and electrical specifications for the MMC are given in “The MultiMediaCard System Specification” that is updated and published from time-to-time by the MultiMediaCard Association (“MMCA”) of Cupertino, Calif. Versions 2.11 2.2, and 3.1 of that Specification, dated June 1999, January 2000, and June 2001, respectively, are expressly incorporated herein by this reference. MMC products having varying storage capacity up to 128 megabytes in a single card are currently available from SanDisk Corporation. These products are described in a “MultiMediaCard Product Manual,” Revision 2, dated April 2000, published by SanDisk corporation, which Manual is expressly incorporated herein by this reference. Certain aspects of the electrical operation of the MMC products are also described in co-pending patent applications of Thomas N. Toombs and Micky Holtzman, Ser Nos. 09/185,649 and 09/186,064, both filed Nov. 4, 1998, and assigned to SanDisk Corporation. The physical card structure and a method of manufacturing it are described in U.S. Pat. No. 6,040,622, assigned to SanDisk Corporation. Both of these applications and patent are also expressly incorporated herein by this reference.
The newer SD Card is similar to the MMC card, having the same size except for an increased thickness that accommodates an additional memory chip. A primary difference between them is that the SD Card includes additional data contacts in order to enable faster data transfer between the card and a host. The other contacts of the SD Card are the same as those of the MMC card in order that sockets designed to accept the SD Card will also accept the MMC card. The electrical and functional interface with the SD card is further made in such a way that the sockets designed to accept the SD card can also be made to accept the MMC card, as is described in PCT published application number 02/15020 of Yoram Cedar, Micky Holtzman, and Yosi Pinto, published Feb. 21, 2002, and hereby incorporated by this reference. Certain aspects of the SD card are described in U.S. patent application Ser. No. 09/641,023, filed Aug. 17, 2000, which application is incorporated herein by this reference. (The specifications of the SD card are available to member companies of the SD Association (SDA).)
Cards made according to the ISO/IEC 7816 standard are of a different shape, have surface contacts in different positions, and a different electrical interface than the MMC and SD Cards. The ISO/IEC 7816 standard has the general title of “Identification cards—Integrated Circuit(s) Cards with Contacts,” and consists of parts 1-10 that carry individual dates from 1994 through 2000. This standard, copies of which are available from the ISO/IEC in Geneva, Switzerland, is expressly incorporated herein by this reference. ISO/IEC 7816 cards are particularly useful in applications where data must be stored in a secure manner that makes it extremely difficult or impossible for the data to be read in an unauthorized manner. The small ISO/IEC 7816 cards are commonly used in cellular telephones, among other applications.
Recently, cards have been described that allow multiple modules having different functionalities to be attached to the host. These include a single card having multiple modules and cards where the modules are distributed between several cards, but where a first card attaches directly to the host and the other cards attach to the first card rather than directly to the host, such as is described in co-pending U.S. patent application Ser. No. 09/653,062, filed Sep. 1, 2000, which is hereby incorporated by reference. For example, the modules could include a memory module and an input-output module, where both modules are in a single, combination card, or where a memory card is designed to attached to the host on one end and attach to an input-output card on the other end. Such multi-module cards need to be designed so that they may operate with the host in a fast, efficient and convenient manner.